Sphygmomanometric control system



Nov. 5, 1957 H. BOUCKE 2,811,964

SPHYGMOMANOMETRIC CONTROL SYSTEM Filed March 27, 1956 n I w 42- 1| L INVENTOR HEM/z BOL/CKE ATTORNEY United States Patent SPHYGMOMANOMETRIC CONTROL SYSTEM Heinz Boucke, Tubingen, Germany, assignor to Radio Patents Company, a partnership Application March 27, 1956, Serial No. 574,259

11 Claims. (Cl. 1282.05)

The present invention relates to sphygmomanometers or blood pressure measuring devices, more particularly to devices of the type comprising an inflatable occluding pressure cuff adapted to be applied to an extremity, such as the upper arm, and an indicating device, such as a stethoscope, heart microphone, etc., applied to an artery at a point located distally from said cuff for determining the characteristic sounds upon passing of the occluding pressure through the upper (systolic) and lower (diastolic) blood pressures, while the cult is gradually defiated during a blood pressure measurement.

in the conventional use of sphygmomanometric devices of this type, the physician first closes an escape or leak valve connected to the occluding cuff, whereupon he inflates the cufi by means of a pump, such as a rubber bulb etc., to a pressure above the systolic pressure to stop the circulation through the artery. He then slightly opens the leak valve to allow the air in the cuff to escape gradually, while continuously manipulating the valve as the pressure in the cufi decreases to maintain a substantial constant escape velocity or uniform decrease of the cuff pressure. At the same time the physician observes a suitable pressure gauge indicating the cuff pressure, while listening, by means of a stethoscope or the like, to the characteristic sounds when the cuff pressure passes through the systolic and diastolic blood pressure of the patient.

Alternatively, the systolic and diastolic pressures may be determined by observing a suitable indicator or recording device connected to a heart microphone or the like pick-up device applied to an artery at a point distally from the occluding cufr", in a manner readily understood.

In the operation of devices of this type the physicians attention is detracted continuously by the control and manipulation of the escape valve, which not only may result in erroneous reading of the blood pressure but may necessitate a repetition of the measurement due to jamming of the valves as well as other causes and defects.

Accordingly, an important object of the present invention is the provision of means in connection with a blood pressure determining device of the type described, by which a continuous and substantially uniform escape of the air from the occluding pressure cult is insured, without requiring the continuous attention of/ or manipulation by the operator.

A more specific obect of the invention is the provision of a control device to effect a substantially continuous and linear reduction of the pressure in the occluding cuff by simply operating a key or equivalent control element, substantially without requiring repeated .or continuous manipulation and adjustments.

The above and further objects, as well as novel aspects and features of the invention, will be better understood from the following detailed description of a preferred embodiment taken in reference to the accompanying drawing, forming part of this specification and wherein:

Fig. 1 is a schematic diagram of a pressure control system for a sphygmomanometer or blood pressure measuring device and embodying the principles of the invention;

Fig. 2 is a partial view of Fig. 1, illustrating a modification thereof; and

Figs. 3 and 4 are isometric and side views, respectively, of a constructural embodiment of a device according to the invention suitable for use in connection with conventional blood pressure measuring devices, both manual and automatic.

Like reference numerals identify like parts in the different figures of the drawing.

The above objects of the invention are attained principally by the provision of a pair of escape or leak valves operated consecutively by means of a single control member, such as a key or the like, in such a manner as to connect the first of said valves to the occluding cuff by an initial movement of the control member and to connect the second valve to said cuff during the subsequent or final movement or adjustment of said control member. The first escape valve is so designed or constructed as to effect a favorable, such as linear, reduction of the cuff pressure during the higher partial pressure range during the course of a blood pressure measurement, while the second valve is so designed as to cause a uniform pressure reduction during the lower pressure range or final period of the measurement and/or to effect a complete removal or deflation of the cuff at the end of the measuring operation.

For this purpose, the first leak valve may advantageously be of the linearized type, to insure a uniform escape velocity and a substantially linear reduction of the cuff pressure, while the second valve serves mainly for emptying the cuff and to restore the device to a condition for starting a new operating or measuring cycle. All that is necessary, therefore, for the operator in such a case is to initially depress the key or the like to a stop point marked by a slight resistance, click stop, etc. to open the first leak valve and to cause a substantially linear pressure reduction in the cuff, whereupon the key is further depressed to open the second valve and to complete the deflation and/ or to fully empty the cuff at the end of the measuring operation. Such a device can be used both in connection with the conventional manually operated sphygmomanometers or with semiautomatic blood pressure measuring devices having means for automatically inflating and defiating the cuff and to visually indicate or record the characteristic sounds or pressure variations upon passing through the systolic and diastolic pressure values.

Referring more particularly to Fig. 1 of the drawing, the numeral 10 indicates schematically a blood pressure or occluding cuff connected to a pump 11 (rubber bulb, etc.) in series with a pressure gauge or manometer 12 through a tube or connecting line 13. Connected to the tube 13 is a further tube 14 leading to a pair of branches 14a and 14b. Connected in the branch 14a is a first control valve, this branch terminating in a leak or escape valve 34. The latter may be in the form of an adjustable needle valve or nozzle or of any other suitable construction. Similarly connected in the branch 14b is a control valve branch 14b terminating in an escape valve or nozzle 35 similar to the valve 34.

Control valve 140, in the example shown, comprises an inner closed rotatable cylindrical valve member 15 journalle-d in an outer sleeve or cylindrical valve member 16. Similarly, control valve 14d has an inner rotatable member 17 and an outer stationary member 13. The outer member 16 of the valve 140 has a pair of diametrically opposed ports 2% and 21 communicating with the branch line 14a, While the inner valve member 15 has a pair of cooperating ports 22 and 23 displaced relative to the ports 25) and 21 in the normal or inoperative position, as shown in the drawing. The outer member 18 of the control valve 14d has a pair of ports 24 and 25 communicating with the branch line 1412, while the inner valve member 17 has a pair of cooperating ports 26 and 27 also displaced relative to the ports 24 and 25m the normal or inoperative position' a The inner valve member of thecontrol valve 14c has connected to it a lever or link 28 to which is secured a key 30 or the like operating member. As a result, upon depressing the key 30 in the direction of the arrow 01, against the action of a spring 29 or the like, the valve member 15 is rotated in clockwise direction, thus causing its ports 21 and 22 to register with the ports and 21 and to open the valve 140. This operation takes place when the key is depressed within a predetermined initial displacement fixed by a click stop or equivalent abutment. In the example shown in the drawing, the first key position 30' is determined by an extension or actuating member 32 of the inner valve member 17 of the valve 14d.

In operation, the key 30 upon engaging the member 32 is held in this position, to allow the air in the cuff 10 to escape through the valve 140 and the nozzle 34. The latter may be so designed and/ or adjusted as to effect a favorable, that is, uniform decrease of the pressure in the cuff 10 during the first stage or period of the measuring operation. The key 30 is then further depressed until reaching a position 30" determined by a stop or abutment (not shown), whereby to effect anticlockwise rotation of the valve member 17 and opening of the valve 14d. As a result, the air is now allowed to escape through the valve or nozzle which may be so designed and/or adjusted as to effect most favorable pressure reduction during the second stage or period of the measuring operation. Valve 14c may be closed during the opening of valve 14d with the relative location and size of the ports 29, 21 and 22, 23 as shown, or valve 140 may be maintained in its open position during the opening of valve 14d by a proper relative design of the ports, in a manner readily understood.

In practice the valves 34 and 35 may be designed with an adjustable opening or nozzle such as to result in an average discharge velocity during the respective partial cuff pressure ranges. As an example, assuming a total operating range from a pressure of about 200 mm. to a pressure of about mm. mercury, the nozzle 34 is adjusted with a relatively small opening to cause a practically uniform pressure release within a range from 200 to mm., while the nozzle 35 is adjusted with a relatively greater opening to effect a uniform pressure release from 120 to 40 mm. In this case, the operator first adjusts the key 30 to its intermediate position 30' and upon reaching a cuff pressure of 120 mm., he moves it to its final position 30".

Alternatively, the escape of the air in the cuff 10 or reduction of the cuff pressure during a blood pressure measuring operation or cycle may be effected in the first key position 30' by the valve 14c and nozzle 34, while further depression of the key to the position 39" and opening of the valve 14d, serves to fully release the air and empty the cuff preparatory to a new measuring cycle. According to this embodiment and operation of the invention, the escape valve or nozzle 34 is advantageously designed and/or provided with suitable means to cause a gradual or linear release of the cuff pressure, such as by the use of an automatic control valve maintaining a substantially constant pressure at the input end of the leak or nozzle 34.

Referring to the above example, the operator first moves the key 30 to its position 30' and holds it there during the entire measuring operation, whereupon, that is, upon reaching a pressure of about 40 mm., he depresses the key fully to release the remainder of the pressure and restore the blood circulation.

An arrangement of the latter type is shown in Fig. 2. According to the latter, there is provided a further flexible valve member or elastic tube 37 consisting of rubber or the like and connected between the control valve and the escape valve 34. The cross-section of this tube is automatically controlled by the input pressure of the valve 34 by the provision of a bellows 38 or equivalent pressure sensitive element connected between the tube 37 and the valve 34. The bellows has an extension 40 engaging one side of the valve tube 37 whose other side engages a fixed stop or abutment 41.

As a result, the pressure on the output side of the tube 37, that is, the input pressure of the escape valve 34 is maintained substantially constant, in such a manner as to effect a uniform or linear release or escape of the air from the nozzle 34, thereby in turn, causing a uniform or linear decrease of the pressure in the cuff 10. More specifieally, an increase of the pressure at the input side of the valve 4 causes the bellows 38 to expand, whereby to reduce the cross-section of the valve tube 37 until the original pressure has been restored. On the other hand a decrease of the pressure at the input side of valve 34 causes the bellows 38 to contract, thus allowing more air to flow through the valve tube 37 until the pressure has again attained its predetermined value.

By the proper design and/or adjustment of the automatic control valve 37, 38, 40 and 41, the input pressure of the escape valve 34 may be maintained at a desired constant value, resulting in a uniform or linear decrease of the pressure in the cuff 10.

The pressure control system according to the invention may be structurally embodied in a unitary device suitable for use in connection with conventional sphygmomanometers or semiautomatic blood pressure determining devices. Thus, there is shown, by way of example, in Figs. 3 and 4 a casing 41 within which are mounted the various control valves and auxiliary parts and which is fitted with suitable means for effecting connection with a pump and pressure cuff. For this purpose, the tubular extensions 42 and 43 protruding from the front and side walls may serve for the connection of the pump 11 and the cuff 10, Fig. 1, while the key 30 may be mounted on the outside of the front wall and the pressure gauge 12 may be mounted near the top wall as shown in the drawing, or in any other suitable manner.

While a special type of control valve 140 and 14d has been shown for illustration, equivalent valves of different design or construction may be employed for the purpose of the invention, or the control valves 14c and 14d may be structurally combined with their respective leak valves 34 and 35 into a single valve unit, the essence of the invention residing in the combination of the parts (valves, common operating member etc.) and cooperative relation as disclosed and described in detail herein.

Iii th'e foregoing the invention has been described with reference to a specific illustrative device. It will be evident, however, that modifications and variations, as well as the substitution of equivalent parts and elements for those shown for illustration, may be made without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawing are accordingly to be regarded in an illustrative rather than in a limiting sense.

I claim:

1. In a sphygmomanometerhaving an inflatable pressure cuff and means to release the pressure within said cuff during a blood pressure measuring operation, said means comprising a pair of valve means connected to said cuff and common control means for said valve means actuatable along a predetermined operating path, whereby to first open one of said valve means by operation of said control means to an intermediate position within said operating path and to subsequently open the other valve means by further operation of said control means beyond said intermediate position.

2. In a sphygmomanometer having an inflatable pressure cuff and means to release the pressure within said cuff during a blood pressure measuring operation, said means comprising first escape valve means connected to said cuff and designed to effect a substantially uniform pressure reduction within the upper range of cuff pressure during the course of a measuring operation, second escape valve means connected to said cuff and designed to effect a substantially uniform pressure reduction within the lower range of cult pressure during said measuring operation, and common control means for saidfirst and second valve means actuatable along a predetermined operating path, whereby to first open said first valve means by operation of said control means to an intermediate position Within said operating path and to subsequently open said second valve means by continued operation of said control means beyond said intermediate position.

3. In a sphygmomanometer having an inflatable pres sure cuff and means to release the cuff pressure during a blood pressure measuring operation, said means comprising first escape valve means connected to said cuff and designed to effect a gradual reduction of the cuff pressure during the course of a measuring operation, second escape valve means connected to said cuflf and designed to effect a relatively quick release of the cuff pressure, and common control means for said first and second valve means actuatable along a predetermined operating path, whereby to first open said first valve means by operation of said control means to an intermediate position within said operating path and to subsequently open the other valve means by continued operation of said control means beyond said intermediate position.

4. In a sphygmomanometer as claimed in claim 3, including pressure linearizing means to maintain a substantially linear cuff pressure reduction by said first valve means during the course of a blood pressure measuring operation.

5. In a sphygmomanometer having an inflatable pressure cuff and means to release the cuff pressure during a blood pressure measuring operation, said means comprising first and second escape valve means each having a control member and connected to said cuff, a control key actuatable along a predetermined operating path, said key adapted to actuate the control member of said first valve means and to engage and actuate the control member of said second valve means during the final portion of said operating path, whereby to consecutively open said first and second valve means by operation of said key through said operating path.

6. In a sphygmomanometer having an inflatable pressure cuff and means to release the cuff pressure during a blood pressure measuring operation, said means comprising first valve means having a control member and connected to said cufr', said first valve means designed to effect a substantially uniform reduction of the cuff pressure within the upper presure range during the course of a blood pressure measuring operation, second escape valve means having a control member and connected to said cufi,'said second valve means designed to effect a substantially uniform pressure duction within the lower pressure range during the course of a blood pressure measuring operation, a control key actuatable along a predetermined operating path, said key adapted to actuate the control member of said first valve means and to engage and actuate the control member of said second valve at an intermediate position of said poerating path, whereby to consecutively open said first and second valve means by operation of said key through said operating path.

7. In a sphygmomanometer having an inflatable pressure cufi and means to release the cuff pressure during a blood pressure measuring operation, said means comprising first escape valve means having a control member and connected to said cuff, said first valve means designed to effect a substantially uniform pressure reduction during the course of a blood presure measuring operation, second escape valve means having a control member and connected to said cuff, said second valve means designed to effect a relatively quick release of the cuff pressure, a control key actuatable along a predetermined operating path, said key adapted to actuate the control member of said first valve means and to engage and actuate the control member of said second valve means near the end position of said operating path, whereby to cause a uniform cuff pressure reduction by initially operating said key to open said first valve means and to cause a quick pressure release by subsequently operating said key to said end position.

8. In a sphygmomanometer as claimed in claim 6, including pressure linearizing means operatively associated with said first escape valve means, to maintain a substantially linear decrease of the cuff pressure during the course of a blood pressure measurement.

9. In a sphygmomanometer having an inflatable pressure cuff and means to release the cuff pressure during a blood pressure measuring operation, said means comprising a first control valve connected to said cuff, a first leak valve connected to said control valve, a second control valve connected to said cuff, a second leak valve connected to said second control valve, and common operating means for said control valves operable within a predetermined operating path, whereby to first open the first control valve by operation of said operating means to an intermediate position of said operating path and to subsequently open the other control valve by operation of 7 said control means beyond said intermediate position.

10. In a sphygmomanometer as claimed in claim 9 wherein said first leak valve is designed to etfect a substantially uniform pressure release within the upper pressure range during a blood pressure measuring operation and said second leak valve is designed to effect a uniform pressure release during the lower pressure range within said measuring operation.

11. In a sphygmomanometer as claimed in claim 9, including means to cause said first valve to effect a substantially linear pressure release during the blood pressure measuring operation, and said second valve being designed to effect a relatively quick release of the cuff pressure.

References Cited in the file of this patent UNITED STATES PATENTS 

